Torque Converter | Mercedes | 722.6 & 722.9, 5 Speed, MC-18, MC-19 | MC-18
Mercedes transmissions frequently suffer shudder and cold-stall condition. This is often blamed on the converter, but there is no single cause. The number one cause is using the wrong transmission fluid. Mercedes supplies different (costly) fluids for each type of unit. Trying to reduce costs by substituting with standard fluids will cause the shudder condition and also cause other symptoms. Leakage of anti-freeze into the transmission via the radiator will also cause the problem. Vehicle manufacturers require triple-flushing of the transmission to assure thorough removal of the antifreeze. This is necessary to assure complete removal of the contaminant. Many rebuilders always replace the lockup solenoid. Occasionally, it is required to replace the solenoid block and all the solenoids. The block is made of plastic and can be the cause of the problem. This is the factory approach and it is very costly. Complete factory valve bodies is also a solution. Frequently the friction plate is wrongfully blamed for causing the shudder. Experienced rebuilders attribute the condition to internal leaking and they apply leak fixes in different locations within the converter. Since no one can be certain of the exact cause, it is recommended to apply multiple fixes. Currently, the most successful correction is the installation of Tri's spring-loaded, spacer steel plate kit, which is intended to deal with shudder & cold-stalling. The concept is to "bypass" the various issues. Major rebuilders successfully install them in all rebuilds. This is the simplest "drop-in" fix and is very effective and highly recommended. An added benefit is the low cost. Relevant part numbers are: HX-23-13K, which contains one notched steel plate and ten 0.310“ (7.87mm) long springs and HX-23-15K, which contains two notched steel plates and ten 0.510“ (12.95mm) long springs. Genuine Tri-component friction plates have long been a proven companion, favorite among rebuilders.